Review on 12V DC 5.5mm x 2.1mm Car Cigarette Lighter Power Adapter Cable by JacobsParts - 2.5 Feet by Obhed Mac

It supplies electricity, but buyers should be aware that it contains no diodes or other built-in electronics to prevent electricity from draining your device! In principle, current can flow in both directions with this charger. I was using mine to charge an external battery and noticed that when the car was turned off (was plugged into an extra device, just a cigarette lighter plug) my car radio stayed on and wouldn't let me open the car doors because it was drawing power from the device and power to mine radio and other items through this fuse. This is not what I would call "quality". DISCONNECT this charger when not in use, or something bad could happen.